Badiobeceiving appabattjs



v H. K. SANDELL.

Y RADAORECEIVING APPARATUS.

APPLICATION FILED not. 13, 1919.

1,366,953. Patented'Feb. 1,1921.

Ever? fir.

UNITED STATES PATENT OFFICE.

HENRY x. SANDELL, or CHICAGO, ILLINOIS. ASSIGNOR 'ro HERBERT s. MILLS, or

CHICAGO, ILLINOIS.

RADIORECEIVING APPARATUS.

. To all whom it may concern:

- Improvement in Radioreceiving Apparatus,

of which the following is a specificatlon.

The present invention relates to radio receiving apparatus, and more particularly to such apparatus wherein a thermionic or electronic type of space current device is utilized for the detection and amplification of waves received.

In order that the invention may be clearly understood, it is illustrated in the accompanying drawings in certain specific embodiments as applied to the reception of signals transmitted by damped and by undamped waves.

In the drawings:

Figure 1 shows diagrammatically a receiving circuit adapted for use in a system operatmg with damped waves;

Fig. 2 is a diagrammatic view of circuits of a system operating by undamped waves, and including two loop antennae; and

Fig. 3 shows in plan and diagrammatically the relative arrangement of the loop antennee of the apparatus of Fig. 2.

Referring more particularly to the drawings, in Fig. 1 the numeral 10 indicates an antenna of the loop or spiral type, grounded by means of the conductor 11, which has a variable point of connection 12 with the spirals or loops of the antenna, whereby the antenna may be utilized for the reception of waves of different lengths. The antenna is connected by a suitable conductor 13 with the grid 14 of a suitable space current device or audion 15. A variable condenser 16 may be interposed in series in the conductor leading to the grid. The filament 17 of the audion is heated by a suitable heating circuit, for example, the circuit comprising battery 17, variable resistance 18, conductor 19, filament 16, conductor 20 and the return conductor 21, completing the circuit to the battery. The plate circuit may include the receiving device 22, or may be provided with suitable connections for regenerative or cascade coupling or for further amplification, as desired. As illustrated in Fig. 1, the plate circuit comprises the plate 23, conductor 24 leading to the battery 25, conductor 26, the receiving device 22 and the conduc- Specification of Letters Patent.

Application filed October-'13, 1919.

Patented Feb. 1, 1921.

Serial No. 330,445.

tor 27 which is connected with the conductor 20 leading in to the filament 16.

In case it is desired to apply the invention to the reception of signals transmitted by undamped waves, a second antenna of loop or spiral type may be interposed in the plate circuit, this antenna being brought in quite close proximity to the antenna connected with the grid and mounted rotatably so that 1ts angular position with relation to the antenna connected with the grid may be varied at will.

As illustrated in Figs. 2 and 3, the numeral 30 indicates an antenna of loop or spiral type having a variable connection 31 with the ground and connected to conductor 32, condenser 33 and conductor 34 to the grid 35 of the audion 36. The filament 37 of the audion is heated in the usual manner by the circuit from battery 38, as regulated by variable resistance 39. The late electrode 40 is connected in the circuit with the B-battery 41, receiving device 42, the loop or spiral antenna 43 and the filament 37. The connection of the antenna 43 in the plate circuit is variable as indicated at 44. The antenna 43 is mounted in proximity to the antenna 30 upon a vertical rotatable standard 45, being insulated therefrom. As a result of this construction, the antenna or loop 43 may be rotated so as to assume any desired angle relative to the antenna 30. Utilizing this arrangement for the reception of signals transmitted by undamped waves, the apparatus being set up and in operative condition, the angular position of the loop 43 relative to the loop 30 is varied slowly until the signals become audible in the receiver. It is readily apparent that in this system any suitable arrangement of connections or apparatus for regenerative or cascade coupling or for greater amplification may be utilized without departing from the invention. It is likewise apparent that this system may be utilized for the reception of damped waves, in which instance the two loops or antennae together act as a regenerative coupling when properly positioned relative to each other. This position is readily determined by rotating one loop relative to the other while listening at the receiving device.

Although the present invention has been described in connection with certain details as to apparatus and their arrangement, it is not intended that the details thus set forth are to-be" regarded as limitations upon the scope of the invention, except in so far as included in the accompanying claims.

I claim:

1. In a radio receiving device, an aerial having a single ground connection, an audion, a single current carrying connection between the grid of said audion and the aerial, and a plate circuit having terminals within the audion at the plate and filament thereof, said plate circuit including receiving means and an aerial, the latter being in inductive relationship to the first-mentioned aerial.

2, In a radio receiving device, a grounded loop antenna, an audion, a single currentcarrying connection between the grid of said audion and the antenna, and a plate circuit having terminals Within the audion at the plate and'filament thereof, said plate circuit including receiving means and a loop antenna, the latter being in proximity to the first-mentioned grounded antenna.

3. In a radio receiving device, a grounded loop antenna, an audion, a single current carrying connection between the grid of said audion and the antenna, and a plate circuit having terminals within the audion at the plate and filament thereof, said plate'circuit including receiving means and a loop antenna, the latter being in proximity to the first-mentioned grounded antenna, and its angular position being adjustable relatively thereto.

HENRY K. SANDELL. 

